1. Field of the Invention
The present invention relates to a technique of obtaining plural viewpoint images by photo-electrically converting a luminous flux passing through different regions of a single photographing optical system.
2. Description of the Related Art
Conventionally, an imaging device having an optical system as shown in FIG. 16 has been known (JP2009-527007A).
In FIG. 16, a luminous flux passing through different regions in a left-right direction (vertical or crosswise direction in the drawing) of a main lens 1 and a relay lens 2 is split by a mirror 4, and the split luminous fluxes are photo-electrically converted by image sensors 7 and 8 via focus lenses 5 and 6.
FIGS. 17A to 17C are diagrams illustrating a difference in an object image focused on an image sensor due to a difference in an object distance (distant and close). Note that, in FIGS. 17A to 17C, the mirror 4 shown in FIG. 16 is abbreviated to compare the split states of the object image. As shown in FIGS. 17A to 17C, by obtaining the object image split in the left-right direction (vertical direction in the drawings) via the image sensors 7 and 8, obtain a left-viewpoint image and a right-viewpoint image (3D image) having different parallaxes depending on the object distance can be obtained.
Moreover, another related art is disclosed in JP2009-168995A.
Techniques of photo-electrically converting a luminous fluxes passing through different regions of a pupil of a photographing optical system through the use of image sensors and detecting a focusing state of the photographing optical system based on a phase-difference between a first image signal and a second image signal obtained by the conversion are known in the art (JP2004-191629A and JP2009-244858A).